The present invention relates to a stator for use, for example, in a torque converter of an automatic transmission for an automobile.
FIGS. 19 and 20 illustrate a stator described in U.S. patent application Ser. No. 09/466,854. In this stator, a notched type one-way clutch 57 is constituted by a strut 54 and a notched plate 55, the strut 54 being accommodated, together with a coiled spring 53, in a pocket portion 52 formed in a resinous stator body 51, the notched plate 55 being combined with the stator body 51 in a relatively rotatable manner and having an engaging recess 56 with which the strut 54 comes into engagement in one rotational direction. In the pocket portion 52, moreover, a swing angle limiting portion 58 for limiting a swing motion of the strut 54 up to a predetermined angle is formed integrally by molding.
In the stator illustrated in FIGS. 19 and 20, however, a relatively large spacing 59 is formed between the strut 54 and the swing angle limiting portion 58 and in a rotational direction (the right and left direction in the figures) of the stator, there arises the following problem.
When the notched plate 55 rotates (in arrow A direction) relatively with respect to the stator body 51 in a direction in which the one-way clutch 57 runs idle, the strut 54 is dragged by the notched plate 55 and moves in the same direction within the pocket portion 52, which movement may continue up to the position indicated with a chain line in FIG. 19. In this case, an engaging portion 54a of the strut 54 comes into strong contact at a tip end thereof with an anti-engaging face 52a of the pocket portion 52, so that the anti-engaging face 52a wears gradually, which may impede the operation of the clutch 57.
According to the structure of the stator shown in FIGS. 19 and 20, the strut 54, which is accommodated in the pocket portion 52 together with the coiled spring 53, is in direct contact with a bottom 52b of the pocket portion 52. Therefore, when the strut 54 swings with idle running of the clutch 57, the strut 54 slides on the bottom 52 of the pocket portion 52. As this sliding motion is repeated, the bottom 52b of the pocket portion 52 wears gradually, which may impede the operation of the clutch 57.
It is an object of the present invention to provide a stator capable of preventing wear of such inner faces as the non-engaging face and bottom of the pocket portion and hence capable of preventing the operation of the one-way clutch from being impeded by such wear.
For achieving the above-mentioned object, according to claim 1 in the present invention there is provided a stator including a notched type one-way clutch, the notched type one-way clutch having a strut which is accommodated, together with a spring, within a pocket portion formed in a resinous stator body and also having a notched plate, the notched plate being combined with the stator body in a relatively rotatable manner and provided with an engaging recess with which the strut comes into engagement in one rotational direction, with a swing angle limiting portion being formed in the pocket portion to limit a swing motion of the strut up to a predetermined angle, and wherein a movement limiting portion for limiting the movement of the strut toward an anti-engaging face side within the pocket portion is formed on an engaging face side of the swing angle limiting portion integrally by molding.
According to claim 2 in the present invention there is provided, in combination with the above claim 1, a stator wherein a spring is disposed between a bottom of a spring mounting portion and an engaging portion of the strut accommodated in the pocket portion in such a manner that the spring can expand and contract axially of the stator, the spring mounting portion being in the shape of a bottomed hole which is open to an end face of the swing angle limiting portion.
According to claim 3 in the present invention there is provided, in combination with the above claim 2, a stator wherein the notched plate-side face of the engaging portion of the strut is formed in a generally  shape in section comprising a base end-side slant face and a tip end-side slant face, the tip end-side slant face being smaller in the angle of inclination than the base end-side slant face and being pushed against the notched plate by the resilience of the spring during idle running of the clutch.
According to claim 4 in the present invention there is provided, in combination with the above claim 2, a stator wherein the strut is formed so that an end portion of the strut located on a rearmost side in the relative rotation, which end portion comes into contact with an end face portion of the notched plate during idle running of the clutch, is positioned on a front side in the relative rotation with respect to an axis of the spring mounted in the bottomed hole-like spring mounting portion.
According to claim 5 in the present invention there is provided, in combination with the above claim 2, a stator wherein the strut is formed so that an end portion of the strut located on a rearmost side in the relative rotation, which end portion comes into contact with an end face portion of the notched plate during idle running of the clutch, is positioned at the same circumferential position as an axis of the spring mounted in the bottomed hole-like spring mounting portion.
According to claim 6 in the present invention there is provided, in combination with the above claim 4 or claim 5, a stator wherein a cutout portion is formed in a tip end of the engaging portion of the strut to realize the structure described in claim 4 or claim 5.
According to claim 7 in the present invention there is provided a stator including a notched type one-way clutch, the notched type one-way clutch having a strut which is accommodated, together with a spring, within a pocket portion formed in a resinous stator body and also having a notched plate, the notched plate being combined with the stator body in a relatively rotatable manner and provided with an engaging recess with which the strut comes into engagement in one rotational direction, with a swing angle limiting portion being formed in the pocket portion to limit a swing motion of the strut up to a predetermined angle, the spring being formed by a plate spring, the plate spring having an inner surface reinforcing portion formed integrally by molding and interposed between the strut and a bottom of the pocket portion.
As in the stator of claim 1 constructed as above, if a movement limiting portion for limiting the movement of the strut in a direction of an anti-engaging face within the pocket portion is formed on an engaging face side of the swing angle limiting portion in the pocket portion integrally by molding, it becomes possible to limit the strut movement toward the anti-engaging face side and prevent the strut from contacting the anti-engaging face. Out of both end faces in the rotational direction within the pocket portion, the one which supports the strut in an engaged state of the one-way clutch corresponds to the engaging face, while the opposite face corresponds to the anti-engaging face.
In the stator of claim 2 constructed as above, since a spring is disposed between the bottom of a bottomed hole-like spring mounting portion which is open to an end face of the swing angle limiting portion and an engaging portion of the strut accommodated in the pocket portion, the spring thus disposed being capable of expanding and contracting axially of the stator, the strut and the spring can be mounted completely in the pocket portion merely by first inserting the spring into the spring mounting portion and then putting the strut on the spring. Thus, the spring compressing work can be omitted at the time of mounting the strut.
In the stator of claim 3 constructed as above, since the notched plate-side face of the engaging portion of the strut is formed in a generally  shape in section comprising a base end-side slant face and a tip end-side slant face, the tip end-side slant face being smaller in the angle of inclination than the base end-side slant face and being pushed against the notched plate by the resilience of the spring during idle running of the clutch, an outer corner portion at the boundary between the base portion and the engaging portion of the strut can be prevented from interfering with an end face portion of the notched plate under an axial force of the spring at the tip end-side slant face of the strut.
According to claim 4 constructed as above, since the strut is formed so that an end portion of the strut located on a rearmost side in the relative rotation, which end portion comes into contact with an end face portion of the notched plate during idle running of the clutch, is positioned on a front side in the relative rotation with respect to an axis of the spring mounted in the bottomed hole-like spring mounting portion, the engaging portion of the strut, which is biased resiliently by the spring, is pushed against the end face portion of the notched plate and a turning moment is developed in a direction in which the base portion of the strut is received deep in the pocket portion. In other words, a turning moment is not developed in a direction in which the base portion of the strut is pushed out from the pocket portion, so that the base portion of the strut is not pushed out from the pocket portion and an outside corner portion at the boundary between the base portion and the engaging portion can be prevented from interfering with the end face portion of the notched plate.
According to claim 5 constructed as above, since an end portion of the strut located on a rearmost side in the relative rotation, which end portion comes into contact with an end face portion of the notched plate during idle running of the clutch, is positioned at the same circumferential position as an axis of the spring mounted in the bottomed hole-like spring mounting portion, a turning moment, also in this case, is not generated in a direction in which the base portion of the strut is pushed out from the pocket portion. Therefore, the base portion is not pushed out from the pocket portion and an outside corner portion at the boundary between the base portion and the engaging portion of the strut can be prevented from interfering with the end face portion of the notched plate.
For realizing the structure described in claim 4 or claim 5 it is preferable to form a cutout portion in a tip end of the engaging portion of the strut as in claim 6 so that the position of the end portion of the strut on the rearmost side in the relative rotation which end portion comes into contact with the end face portion of the notched plate during idle running of the clutch be shifted to the front side in the relative rotation.
According to claim 7 constructed as above, since an inner surface reinforcing portion is interposed between the strut and the bottom of the pocket portion, it is possible to prevent the strut from coming into direct sliding contact with the bottom of the pocket portion.